Slow, deep breathing (SDB) is a common pain self-management technique. Stimulation of the arterial baroreceptors and vagal modulation are suggested, among others, as potential mechanisms underlying the hypoalgesic effects of SDB. We tested whether adding an inspiratory load to SDB, which results in a stronger baroreceptor stimulation and vagal modulation, enhances its hypoalgesic effects. Healthy volunteers performed SDB (controlled at 0.1 Hz) with and without an inspiratory threshold load. Controlled breathing (CB) at a normal frequency (0.23 Hz) was used as an active control. Each condition lasted 90 s, included an electrical pain stimulation on the hand, and was repeated four times in a randomized order. Pain intensity, self-reported emotional responses (arousal, valence, dominance), and cardiovascular parameters (including vagally-mediated heart rate variability) were measured per trial. A cover story was used to limit the potential effect of outcome expectancy. Pain intensity was slightly lower during SDB with load compared with normal-frequency CB, but the effect was negligible (Cohens d < 0.2), and there was no other difference in pain intensity between the conditions. Heart rate variability was higher during SDB with/without load compared with normal-frequency CB. Using load during SDB was associated with higher heart rate variability, but less favorable emotional responses. These findings do not support the role of baroreceptor stimulation or vagal modulation in the hypoalgesic effects of SDB. Other mechanisms, such as attentional modulation, warrant further investigation.

中文翻译：

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控制呼吸和疼痛：呼吸频率和吸气负荷调节心血管自主反应，但不调节疼痛

缓慢深呼吸 (SDB) 是一种常见的疼痛自我管理技术。除其他外，建议刺激动脉压力感受器和迷走神经调节作为 SDB 镇痛作用的潜在机制。我们测试了在 SDB 中增加吸气负荷，从而导致更强的压力感受器刺激和迷走神经调节，是否会增强其镇痛作用。健康志愿者在有和没有吸气阈负荷的情况下进行 SDB（控制在 0.1 Hz）。正常频率 (0.23 Hz) 的受控呼吸 (CB) 用作主动控制。每个条件持续 90 秒，包括手部电痛刺激，并以随机顺序重复四次。疼痛强度，自我报告的情绪反应（唤醒，效价，支配），每次试验都测量了心血管参数（包括迷走神经介导的心率变异性）。封面故事被用来限制结果预期的潜在影响。与正常频率 CB 相比，负载 SDB 期间的疼痛强度略低，但效果可忽略不计（Cohensd  < 0.2），并且在不同情况下的疼痛强度没有其他差异。与正常频率 CB 相比，有/无负荷 SDB 期间的心率变异性更高。在 SDB 期间使用负荷与较高的心率变异性相关，但不太有利的情绪反应。这些发现不支持压力感受器刺激或迷走神经调节在 SDB 的镇痛作用中的作用。其他机制，例如注意力调节，需要进一步研究。